Telephone-muffler.



M. WEIL.

TELEPHONE MUFFLER. APPLICATION FILED JUNE 27, 1912.

1,058,120 Patented Apr. 8, 1913 o l I gvweni'oz wwm m. h LJ 3%) AM Gl tch n11 mouth or lips.

PATENT OFFICE.

MAXIMILIAN WEIL, OF NEW YORK, N. Y.

. TELEPHONE-MUFFLER,

To all whom) it may concern:

Be it known that I, MAXIMILIAN VVEIL, a citizen of the United States, residing in New Yorkcity, county of New York, and State of New York, have invented a new and useful Improvement in Telephone- Mufliers, of which the following is a specifica'tion.

This invention relates to means whereby a person may talk into a telephone transmitter without being heard by others in the same room. It is based on the principle that sound waves requirea ponderable, elastic medium for their transmission, and consequently cannot pass through a space wherein there'is a vacuum.

The device, which is preferably in the nature of an attachment, accordingly comprises a muffler, hood or chamber having double .walls with a vacuum between, together with a mouthpiece formed so as to prevent sound waves passing directly from the mouth into the outside atmosphere. Consequently, the sound waves emanating from the mouth can only enter the muffler, and there they are absolutely prevented from penetrating the vacuum-j acketed walls.

In the accompanying drawings showing an illustrative embodiment of the invention: Figure 1 is a side elevation of a transmitter with the mufiier attached, portions being broken away; Fig. 2 is a sectionon the line 22 of Fig. 3; and Fig. 3 is a front elevation of the muflier.

The muliler 1 is preferably constructed as an attachment capable of being applied to existing transmitters, one of which is illustrated and designated 2. It comprises a tube or hood or chamber open at the back, where it is applied to the front wall of the diaphragm case 3, and provided at .the front with a mouthpiece 4 made so as to conform approximately to the mouth of the speaker, that is to say, of a size and shape to receive fairly closely the average human I At the back the walls" are preferably reentrant so as to form a flaring sound-collector 5 projecting forward from the usual opening or group of openings in the front wall of the diaphragm case into the interior of the chamber formed by the mufiier when seated against said wall. When the device is constructed in this-manner it will be observed that it is necessary to remove the usual telephone mouthpiece Specification of Letters Patent.

Patented Apr. 8, 1913.

Application filed June 27, 1912. Serial No. 706,133.

before applying the attachment. The walls of the mufiier are made double with a vacuum in the space 6 between. Preferably the mouthpiece 4 and thesound-collector 5 are solid. The deviceas just described may be made of glass or other suitable material, and it may be all in one piece or otherwise. The shape may be varied, but it is preferably narrowest at the throat of the mouthpiece, whence it widens out, being at the back of approximately the same diameter as the diaphragm case.

The muiiler is attached to the diaphragm case by a plurality of suitable spring fingers 7, wh ch project rearward and are formed to spring over and embrace the sidesof such case, the device being thus adaptable to transmitters of varying dimensions and forms. The said fingers are preferably carried by a wire 8 which encircles the rear end of the mufller and is seated in a groove or embedded in the surface of the material. Agasketfi of rubber or other suitable material is interposed between the rear end of the muffler and the diaphragm case, so as to make a sound proof and 'airproof joint. Pin-hole openings 10 are .formed through .the walls of the muffler at the region of the throat for the purpose of relievin any excess of pressure that may exist in t e speaking chamber during talking. In use the speaker talks with his mouth well within the mouthpiece.- The majority -of the sound waves are propagated forward and are directed to the center of the diaphragm by the collector 5. In part, however, they strike against the side walls of the muffler and were these solid the sound would penetrate through them and would be audible in the room, but since a vacuum is interposed all of these sound waves are reflected 'and none are allowed to pass through.

Such divergent sound waves may be reflected a number of times within the muflier and may eventually reach the diaphragm but for the most part will be dissipated in heat. "Consequently it is impossible for others in the room to overhear what the person telephoning says.

.What is claimed as new is:

1. A muffler attachment ,for telephone transmitters having a mouthpiece and vacuum-jacketed walls.

2. In a telephone transmitter, the combination with a diaphragm case, of a speakin chamber communicating therewith and a 'apted to receive and prevent the escape of the sound Waves oi speech, being provided with vacuum-jacketed Walls and a mouthpiece constructed to approximately conform to the mouth of the speaker.

A muffler or hood adapted to he attached to the front of the diaphragm case of telephone transmitter having vacuumjacketed walls; a mouthpiece at the front, and a reent r-ant sound-collector at the back.

A muffler or hood having vacuumheted Walls and a mouthpiece, being ted to seat against the front of the diag'm case of a telephone transmitter and ided with attaching means to embrace ides thereof.

A. vacuum-jacketed muffler for attach to telephone transmitters having rem.-

Ward projecting springfingers adapted to clasp the sides of the diaphragm case.

6. An attachment for telephone transmitters, the same comprising a vacuum-jacketed hood to be applied tothe front of the diaphragm case, an encircling Wire seated in the outer surface of said hood, and spring attaching members carried by said wire.

7. The combination or" a mufiler having a mouthpiece and vacuum-jacketed walls and adapted to be applied against the front of the diaphragm case of a telephone transmitter, means. for attaching it thereto, and a, gasket for interposition between the mufiler and the front wall of the diaphragm case.

MAXIMILIAN WEIL.-

Witnesses:

G. H. EMBEY, ll/iAUmoE HOTCHNER. 

